GHSA-v422-hmwv-36x6

body-parser vulnerable to denial of service when invalid limit value silently disables size enforcement

At a glance

Published
Updated
CVE
CVE-2026-12590
CVSS_V3
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Description

### Impact When body-parser is configured with an invalid `limit` option value, such as an unparseable string or `NaN`, `bytes.parse()` returns `null` and the request body size check is silently skipped. Applications that rely on `limit` as their primary safeguard against oversized request bodies will accept arbitrarily large payloads, leading to excessive memory and CPU usage and denial of service. This issue affects applications that pass a programmatically computed or user-configurable value to the `limit` option without validating it first. ### Patches This issue is fixed in [body-parser@2.3.0](https://github.com/expressjs/body-parser/releases/tag/v2.3.0) and [body-parser@1.20.6](https://github.com/expressjs/body-parser/releases/tag/v1.20.6) via [#698](https://github.com/expressjs/body-parser/pull/698). After the fix, invalid `limit` values throw a clear error at parser construction time instead of silently disabling enforcement. `null` and `undefined` continue to fall back to the default limit (`100kb`). ### Workarounds Validate `limit` before passing it to body-parser. For example, parse the value with [`bytes.parse()`](https://github.com/visionmedia/bytes.js) at startup and reject any configuration where it returns `null` or a non-finite number. ### References - [#698](https://github.com/expressjs/body-parser/pull/698): fix PR - [bytes.js](https://github.com/visionmedia/bytes.js): limit parser

Affected packages

PackageVersions
npm · body-parserintroduced 0, fixed 1.20.6
npm · body-parserintroduced 2.0.0, fixed 2.3.0

References

Sources

SourceLicence
OSV.devCC-BY 4.0 — GitHub Advisory Database